The present invention relates to
a peptide suppressing the
phosphorylation of
threonine (T120), the 120th residue of TSPYL5 (testis-specific Y-like
protein 5), which is specifically as follows. The present inventors constructed T120D, the
mutant of the 120th residue
threonine (T120) of TSPYL5, and T120A-TSPYL5
gene and then transfected cells with them in order to investigate the effect of
phosphorylation on T120 residue. As a result, wild-type TSPYL5 and T120D moved into
nucleus and stayed there. But in the case of T120A-TSPYL5, TSPYL5 did not move into
nucleus and instead it was expressed only in
cytoplasm. The
protein could not bind to AKT, either. Instead, ubiquitination of TSPYL5 was increased but SUMOylation was inhibited. Also, the expressions of ALDH1-A1, -A3, CD44
gene and
protein were reduced, and thereby the growth and
metastasis of
lung cancer cells were suppressed and sphere formation was reduced. Based on the observation above, the inventors constructed the
peptide composed of the
amino acid sequences represented by SEQ. ID. NO: 43 or NO: 44 that could inhibit
phosphorylation of the 120th residue
threonine of TSPYL5. The said
peptide can be effectively used as a composition for the inhibition of
cancer cell growth,
metastasis, and
cancer stem cell growth.